Jeans might look odd because the fabric/color echos a faded denim. I'd stick with light-colored cotton trousers. White. Cream. Khaki. Warm tones may work well. You're right about it being casual, and it also looks spring/summer.

I'm not overly familiar with belts from either company, but most fashion belts are made of inferior leather with inferior finishing. I would not expect either of these brands to be an exception.
This brand is made in the US and is a pretty good value for the price:
http://www.torinoleather.com/default.asp

I'm not sure if they're big enough, but Randolph Engineering offers their frames in a variety of sizes. They produce sunglasses and frames for the US military, so I'd guess they supply some large ones.
http://shop.randolphusa.com/sunglasses-c4.aspx

Does it make a difference when wearing it? It seems to me that the "defect" would be undetectable when worn.
Depending on the difference between what you paid and full retail, the cost to remove stitching, glue, and restitch may not be worth the cost. .

For me, it depends on the last with Trickers. I find the country styles mangle my baby toe where the city shoes seem to have a more elongated toe box. With the country styles, I go a half size larger (I'll get a 9.5UK instead of a 9) and use tongue pads and it has worked out well.

Up for your consideration is a pair of unworn chocolate brown suede and calf saddle shoes with a brick-red rubber sole. These handsome shoes are handmade in the United Kingdom by Tricker's. I have another pair of identical shoes, so I'm clearing these out.
They are a 9.5 UK, Fitting 5—which roughly translates to a 10-10.5 D US (determining the appropriate size for your foot is up to you). Comes with original bags, dust cloth, and marketing sheet. The original box is as it...

Up for your consideration is a pair of unworn ankle boots handmade in the United Kingdom by Tricker's. I have another pair of nearly identical boots, so I'm clearing these out.
Please be sure of your size in this brand/last as I cannot guarantee fit. They are a 9.5 UK, Fitting 5—which roughly translates to a 10-10.5 D US (but again, determining the appropriate size for your foot is up to you). Comes with original bags, dust cloth, and marketing sheet. The original box is...